The stator of electrical machines generally comprises teeth and a core back. The function of the teeth is to lead magnetic flux induced in the teeth by a coil arranged round the teeth and, thus, the teeth increases the efficiency of the interaction between the stator and a rotor, in respect of a stator having no teeth. The core back is arranged to magnetically connect the teeth to each other in order to provide a flux feedback loop having low reluctance, i.e. it may be seen as closing the magnetic circuit generating flux for interaction with a rotor.
The stator cores of electrical machines has generally been made of solid soft magnetic material, e.g. iron. One problem with these types of stator cores is that eddy currents is induced in the stator core. To reduce this problem with eddy currents the stator cores of today is made of laminated sheets of electrically insulated soft magnetic material or of iron powder being electrically insulated.